Abstract: Voltage fluctuations in the power grid are one of the important factors affecting the safe and stable operation of the power lines and substations. However, traditional voltage measurement technologies in the power system have problems such as high insulation requirements, large volume, high manufacturing costs, lacking of reliable external power sources, and the need for power outage installation. In response to the above problems, this paper proposes a power line voltage sensing technology based on electric field inversion. By monitoring the rise time of capacitor voltage, the inverse problem of the power line voltage is obtained. First of all, the self-powered measurement principle of inverse problem of power line voltage is introduced. Then, the self-powered voltage measurement structure and the measurement accuracy are analyzed by simulation. Finally, the ultra-low power energy control strategy is proposed, which achieves high-precision acquisition, signal processing, and the transmission of capacitor charging time data. Meanwhile, the test platform is built to verify the measurement accuracy. The results show that under the ultra-low power consumption energy control strategy, the monitoring accuracy of capacitor charging time is within 0.5%, and the voltage measurement accuracy is within 0.86%. Combined with the above-mentioned strategy, it can effectively achieve high precision sensing and wireless communication transmission of line voltage without battery.